Device for use in connection with operation of aircraft



May 4, 1937. HISTARK I 2,078,982

DEVICE FOR USE IN CONNECTION WITH OPERATION OF AIRCRAFT Filed Dec. 7, 1934 8 Sheets-Sheet 1 f0 1 Ms}: skim 3 w I d M @mdt A TTORNEYS.

May 4, 1937. H. STARK 2,078,982

DEVICE FOR USE IN CONNECTION WITH OPERATION OF AIRCRAFT Filed Dec. '7, 1934 a sheets-sheet 2 A37 I A30 40 m9 3/ r i F I I -95 95 QR Q3. /28- j a6 7 A "I. 77 69 J9 2 999 64 I A5 LG I l "'1 i/@/ hi3 L .225 63 6/ g I n I in 3a 09 /0 K55 I an m9 l Qi M m5 /fi M A; A96 5 i I A TTORNEYS.

May 4, 1937.

H. STARK DEVICE FOR USE IN CONNECTION WITH OPERATION OF AIRCRAFT Filed Dec. '7, 1954 8 Sheets-Sheet 3 I fizz/222k:- Hazaee zrk,

BY p 7w MM m.

ATTORNEYS.

May 4, 1937. H. STARK I 2,078,

DEVICE FOR USE IN CONNECTION WITH OPERATION OF AIRCRAFT fill/822102 1 /021100 fiamil "7 M ATTORNEYS.

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May 4, 1937. H. STARK 2,078,982

DEVICE FOR USE IN CONNECTION WITH OPERATION OF AIRCRAFT Filed Dec. 7, 1934 8 Sheets-Sheet 5 A TTORNEYS.

May'4, 1937. H. STARK 2,078,982

DEVICE FOR USE IN CONNECTION WI'I 'H OPERATION OF AIRCRAFT Filed Dec. 7, 1934 8 Sheets-Sheet s BY p 7,44 M m. ATTORNEYS.

A MaLy4,1937- H, STARK 2,078,982

DEVICE FOR USE ml CONNECTION WITH-OPERATION OF- AIRCRAFT 12209222- v Z afacefizrl', ZEUS-.1 fl;

ATTORNEYS.

May 4, 1937. H. STARK 2,078,982

DEVICE FOR USE IN CONNECTION WITH OPERATION OF AIRCRAFT I Filed 05a. 1, 1934 s Sheets-Shet a Zia 06112 0? J ozzza'eflZzzz-i' ATTORNEYS.

Patented May 4, i937 v DEVICE FOR USE IN CONNECTION WITH OPERATION AKRGRAFIL Horace Stark, Washington, D. 0C. Application December 7, 1934, Serial No. 756,535

24 Claims.

The present invention relates to aircraft operation and moreparticularly to a novel system for the operation of airplanes or aircraft and to certain improvements in connection with airplane instruments by which the flying and operation of airplanes is greatly improved and by means of which blind flying is made easier, more certain and less fatiguing to thepilot or operator.

In the system of airplane operation used up to the present time, it has been necessary for the pilot or operator to refer to and to read, at frequent intervals, various instruments necessary for determining factors in flight, including the altimeter, speed indicator, turn indicator, climb indicator, compass, gyro compass and other instruments and to translate the readings into terms of comparison with the desired values or predetermined readings or with the prior readings of the instruments.

As a result of the necessity of constant watch of the instruments, particularly in connection with blind flying, and the necessity of mentally translating the readings of the instruments and of making changes in flightin accordance with the readings, the present system for the operation and control of airplane flight is exceedingly fatiguing and becomes hazardous after a long flight, or when fog or storms are encountered, due to the excessive fatigue involved in properly managing and controlling the plane.

It will be understood that in normal operation of a plane the pilots attention is necessarily scattered, particularly in making landings or takeofis at night, and during fog or bad weather, due to the necessity of reading instruments at the time when the pilots attention is most needed in connection with the operation of the machine.

- At such times the operators attention is generally focused on certain of the instruments, such as the altimeter, the landing beam, air-speed and climb indicator; and in addition it is frequently necessary to giirespecial attention to radio recep- 'l tionj, in order to -"receive"instructions from the handled if it were'not necessary to concentrate f the rnanual handling of the plane.

V Thnecessity of watching instruments and con-- V centratingcn-soinany factors at one time renders f V itsubs'tantially impossible 'for the pilot to iiude th sn e andm mn flighflattitude'of the'plane M 5 and it is "diflicult therefore under such conditions ea somanyfac'tors not directly connected with an ie e iea e r t w i erator with all of the indications or information which he would otherwise obtain by the direct reading of instruments and translating the readings into elements or factors of flight, but the information is transmittedby means of anovel method or system without the necessity of directly reading the instruments, thus permitting him to keep a lookout outside of the plane and to focus his attention directly on the flig-ht attitude of the plane during flight and during take-offs and landing of the plane.

The invention, hereinafter fully described, is based upon the discovery that the principal factors of flight may be transmitted to the pilot by means of tactile stimuli, or through the sense of touch or feel in such a manner as to be already interpreted or translated into comparison with the desired or predetermined value for the particular factor, thereby relieving the pilot of a large part of the concentration heretofore re- L quired in properly conducting a flight.

It will be understood in connection with the invention that while the use of a large number of instruments has become quite general, particularly in the larger commercial planes,;their positions on the instrument board have not become standard-' the fatigue in instrume'nt'flying, in having to concentrate on or reflect as to where to find a particular instrument and then todetermine the reading which must be compared withthe desired reading or factor and with other factors of the flight.

, I The means and devicesas hereinafter described 1;;ney be employed asaseparatexsystem for blind flying, Under tn'econditions in which blind flight or instrument flying is resorted-to, the .pilot, "in "accordance wit hli's' 'invention, controls or operates the plane in exactly 'the :same manner as he does in 'ordinaryfiflyingjn the use: of the invention by receivingzinformation .as to the various flight factors through tactile :stimuli, and

fully under'blind'flying conditions;

It'willbaunderstood from the above that in the use of the invention; both in ordinary: flying, and in 'blind' -flying, the information or' tactile reading of the-various factorsis communicated to the pilotin" general in terms ofrelative yalues n "is thus enabled handle theaircraft more skillto skillfully bring the pli'ijneto theground" or to take dff in the 'w'ay that the plane would be necessity of comparing the indications obtained with the desired reading or factor and relieving the pilot of much of the mental eflort or concentration heretofore required in analyzing or interpreting the information obtained. It will be understood however, that certain readings or factors may be desired without comparison with any base reading, and in such-cases the direct reading may be transmitted to the pilot by the tactile means as will be clear from the following detailed description. A,

The system" hereinafter described obviously greatly simplifies blind flying and serves to promote a feeling of security in the handling of aircraft, particularly because of the fact that in accordance with this invention blind flying and ordinary flying are carried on in substantially the same way. It will be understood, therefore, that the invention is one which renders blind flying easier and more accurate, in that the pilot obtains substantially continuous practice in the use of the devices during ordinary flight and develops a high degree of skill in the use of the invention, so that actual blind flight isrendered relatively easy and simple, The invention serves also to overcome to a great extent the strain and tension in blind flying and-to overcome much of the conscious efiort on the part of the pilot in ,ordinary N flying. It will be recalled that in the ordinary plane the position of the scales or indicators of the various instruments on the instrument board are necessarily spread over a substantial area and it requires a separate reading of each instrument in succession to obtain the necessary information as to the flight factors required.- In the present invention, on the other hand, the various factors are transmitted to the pilot substantially simultaneously, or as coordinated factors to a relatively small area under the hands or fingers of the pilot.

It will be obvious'that' in the use of the invention, the pilot or operator becomes skilled after a time in receiving, through tactile stimuli, the information as to the various flight factoraiso that such information is received substantially subconsciously in much the same manner that the pilot receives flight factor information or becomes aware of the conditions of flight from direct observation by which certain associated factors are coordinated or taken into consideration without particular attention to any one factor alone. In other words, by the use of this invention the pilot receives substantially simultaneouslythe various flight factor tactile stimuli from the tactile units which are connected to the flight factor measuring instruments, or in her words he receives in enect the coordinated impressions at one time from the various instruments, by which he is enabled to guide the aircraft with more or less sub-conscious effort. This inventibnobvdous- 1y obviates the necessity 'of referring to the readings orindications of the instruments on the in- 7 simultaneously with the occurrence of the deviaonce without conscious effort.

rather than absolute values, thus obviating the' tions, so that corrections may be made more or less by instinct rather than by reasoning, so that alterations or corrections in flight are made almost immediately, thereby greatly increasing the accuracy in maintaining the course. The receipt of the flight factor information or indications occurs, furthermore, without requiring visual effort and in a manner so as not to divert the pilots attention from the manual work of operating the plane, whereby the operation and control of the plane is based in effect upon flight factor instrument readings, supplemented by the pilot's observations of the flight attitude of the plane, thus providing increased accuracy and increased safety in the operation of the aircraft.

In the handling or operation of a plane in accordance with the system heretofore used, it is obvious that as relatively slight deviations of the plane from its course occur, such deviations are not ordinarily noticeable to the pilot. For example, if the plane loses altitude to the extent of from 10 to 20 feet, this deviation would not normally be noted by the pilot if the change does not occur abruptly. Similarly, if the plane deviates slightly in direction, the pilot does not ordinarily become aware of it until he again checks up on the magnetic compass or the gyro compass and finds that the plane has deviated from the course to some extent. By the use of the present invention, the informationas to deviations in altitude or in direction is transmitted to the pilot immediately by means of the corresponding tactile units with which his hands are in contact and the deviations thus become apparent to him at The deviations may be corrected immediately therefore as they take place. As a result of making corrections at the time the deviations occur, the plane is maintained on a substantially straight course and at substantially a constant elevation during flight, whereby certain of the instruments, such as the compass, operate with a greater accuracy than can be obtained in ordinary flight, thereby increasingthe efliciency in the handling of the plane, to a considerable extent.

7 One object of the present invention is to provide a new system {for the operation of airplanes,

particularly with reference to lessening the labor involved during a flight incident to the reading of instruments and in translating the readings, checking the flight, or for the making of corresponding corrections in the line of flight or of altitude, whereby flying may be rendered safer both under ordinary flying conditions and under abnormal or dangerous conditions, J

Another object of the invention is to provide a series of flight factor instruments which are adapted to indicate constantly to the pilot, through the operation of tactile units under the hands or fingers of the pilot or by means of manual tactile stimuli, the manner in which, or conditions under which the airplane is flying,

make certain that the indicators of the tactile units agree with readings of the instruments on the instrument board.

' A further object of the invention is to provide a. system for the operation and control'of aircraft through-the sense of touch or "feel by which flight factor information or indications equivalent to the readings of the instruments on the board are automatically transmitted to the 7 in'gof turns. v a a Another object of the invention is to provide;

pilot or translated for him, in effect, into comparison with the particular value or reading which it is desired to maintain.

The indication as to altitude, for example, which is transmitted by tactile means to the pilot may be automatically compared for example with the altitude which it is desired to maintain. In making an ascent or descent to a given level, also, the altimeter tactile instrument may be set for indications with reference to the particular altitude, .so that upon reaching the particular level the tactile unit will give the indication automatically so that no particular attention need be given during the interim to the visual altimeter.

Similarly, by the use of this invention, the degree of turn on the tactile turn indicator is transmitted to the pilot in the manner hereinafter explained, by means of which the pilot is informed whether or not the plane is being turned at an unsafe angle or at an unsafe speed but without the necessity of reading or visually referring to the turn indicator.

Another object of the invention is to provide a system for the controlling of airplane flight which is adapted for determining or indicating certain other factors of flight in plane operation which ordinarily require mental calculations or visual observations, or which involve excessive expenditure of energy in the notation of the factors and which may, in a similar way, be transmitted to the operator through tactile stimuli to the fingers or hands of the pilot.

Another object of the invention is to provide certain novel devices which may be used in connection with the operation of aircraft or the handling of planes so that the system for the operation and flight of commercial airplanes may be modified to permit flying over the same route at different levels, whereby planes travelling in one direction may fiy at one level and those travelling in another direction may fly at another level. It will be apparent that by the use of such a system, signals for one lane or route of travel could be used for aircraft travelling'in opposite directions. Furthermore, by means of the altimeter tactile instrument or levelometer device hereinafter described, the possibility of collision by the use of a single route would be substantially avoided and the cost of operation of aircraft over a given route would be greatly decreased.

A further object of the invention is to provide a system for translating the readings of flight l'factor instruments into manually received tactile indications or registrations which may be communicated to the, pilot through the sense of i touch or feel or his fingers or hands, by which the pilot may be made continuously aware or conscious as to whetheror not the plane is flying in a proper manner, at the desired altitude, speed, or direction and at the desired angle in the-male.

a In

: certain improvements in instruments by "which fsiredgon the. instrument; board for the purpose of source for receiving the flight factors; an added actor iriforn ationdo not agree.

the various essential factors in flight may be indicatedito the'pilot through the sense of touchf ,tude mea uring d vwei ppe which factors may ,also'be directly read if de ,j checking the ffeel indication. n will be obvious" "thatfby the use of an additional independent sense of security is given to the pilot when the wo systemsf agree, and a warning or indicatio'nh 'veii' when the two systems or sources foflflight hereinafter described that this novel system of flying by the sense of touch or feel may be used without substantial effort and without the usual fatigue on the part of the pilot in the making of long flights.

With these and other objects in View the invention comprises the method and apparatus together with the various features of the invention and combinations hereinafter described and more particularly defined in the claims.

The various features of the invention are illustrated in the'accompanying drawings, showing the preferred embodiment of the invention, in which:

Fig. 1 is a sectional view of a portion of the cockpit of an airplane, showing the instrument board therein and also the control mechanism in the plane including the control column or wheel which controls the elevators and ailerons and the pedals-which control the rudder. This view shows also the tactile units or elements for indicating to the pilot through the sense of touch the various essential factors in flight. This view indicates also the preferred position of the adjusting element for setting or adjusting the mechanism of the tactile instrument which indicates altitude with reference to a predetermined altitude or level and also the preferred position of a similar adjusting'device for adjusting the mechanism of the tactile instrument in indicating airspeed with reference to a predetermined speed;

Fig. 2 is a diagrammatic view showing the connections between the tactile indicator elements or buttons on the wheel and the various tactile instruments or apparatus for determining airof the altitude measuring device taken on the section line 4-4 of Fig. 5, showing the preferred form of mechanism by which the movements of aneroid bellows are transmitted to a movable part, the movement of which has been amplified by meansof which altitude as measured with reference toa predetermined altitude, or with reference to sea level, if desired, may be tram-a mitted to the pilot through tactile stimuli;

Fig. 5 is a transverse view in elevation taken on the section line 55 of Fig. 4, parts, being indicated-as broken away to show the detailed construction; 1

,Fig, 6 is a detailed view of a lever and associ- =ated elementjs which operate to control aswitch mechanism ,for opening and closing: a circuit to supply, current for operating" a reversible motor, by which the tactile unit connectedto the alti- Fig. 7 is asectio a1, detailed pl nviewjof the contact-points and associated parts taken'lon the section linefI-I .of-Fig; 5; 1 1 Fig. 8iisf-a sectionalg viewin 'elevati not the the section line,9-,9 of Fig. 8; 4

H h l l0 is e. plan-view taken onth e section line t will be apparent "inhonsideringthemeans u i 1 I Fig. 11 is a cross sectional view of a movable element which is actuated by means of the mechanism of the factor measuring instrument, the said element being directly connected to the tactile unit by means of a Bowden wire or the like, by which the said unit is operated, the said element being shown in. retracted position;

Fig. 12 is a detailed sectional view of the ele-. ment shown in Fig. 11 showing the said element advanced to substantially the extreme upper position;

Fig. 13 is a diagrammatic view, partly in section, showing certain of the main operating elements of the tactile altimeter device together with the relay and electrical circuit by which certain'parts of the device are operated;

Fig. 14 is a view in elevation, partly in section, of the tactile indicating air-speed device by means of which air-speed measurements are transmitted to the pilot by means of a tactile unit;

Fig. 15 is a detailed plan view of a modified form of control column (stick) adapted particularly for small aircraft, this'view showing an arrangement by which tactile stimuli from factor measuring instruments may be transmitted to the pilot by means of tactile units mounted on the stickin a manner; so that it may be grasped with one hand for the transmission of stimuli;

Fig. 16 is a view in elevation of the control column'shown in Fig. 15 showing the manner in which the tactile units may be mounted thereon;

i Fig. 17 is a diagrammatic view of a form of tactile turn indicator, showing electromagnetic devices or solenoids connected in circuit for causing movement of the tactile units on the wheel as the pointer of the turn indicator moves into contact with the points on the turn indicator to complete the circuit;

Fig. 18 is a detailed cross sectional view taken 1 on the section line I8-l8 of Fig. 1, showing the preferred form of electromagnetic unit or solenoid serving to operate the tactile turn indicator units; and

Fig. 19 is a detailed sectional view taken on the line l9-l9 of Fig. 16 showing the preferred mode of mounting the electromagnets or solenoids within the control column or stick for the operation of the tactile units or buttons operatively connected to the tactile turn indicator.

Referring more particularly to Fig. 1 of the drawings, this view indicates the visual instruments of the form usually mounted on the instrument board of a. plane, through the indications of which the pilot guides the ship. These instruments include the magnetic compass 2, the altimeter 4, the air-speed indicator 6, the turn -indicator 8, the climb indicator. ID, a clock or watch. l2,:,the directional gyro compass It, the

- bank indicator 16, the horizon instrument l8, 9.

duplicate altimeter 20, the landing beam instru-- now generally in use except in certain special cases, as hereinafter stated, but is intended to supplement these instruments in such a manner aovacsa as to make flying safer and easier and to permit blind flying in accordance with the system as hereinafter explained in detail.

Referring more in detail to the drawings, it will be understood that the invention embodies a novel system for the blind fiying of airplanes, together with certain novel mechanisms which may be applied to any form of airplane or heavier than air machine, and also in connection with dirigibles, if desired, although it is to be understood that the system as herein described is particularly adapted for use in connection with air planes of the present commercial forms.

In connection with the invention, which is hereinafter fully described, it is to be understood 1:"

chine or become familiar with the positions of the tactile units of the various factor measuring instruments.

The operation of my system and the various units involved and mechanism to be employed will be explained in detail in connection with the essential instruments of flight including the tactile altimeter, the tactile speed indicator, and

the tactile turn indicator, although it is to be understood that the same or similar mechanism may be employed in connection with factor measurements or tactile indications of other instruments of flight, as may be desired, and I do not consider or desire the invention to be limited to the particular instruments as described, therefore.

Referring more particularly to Fig. 2 of the" drawings, it will be apparent how the invention is to be applied in connection with the operation or piloting of aircraft. In applying the invention to the usual form of commercial plane, for example, it will be understood that the various tactile instruments for the'operation of the corresponding tactile elements may be located in any suitable position in the plane, preferably forward of the control column; and the tactile units operated thereby are preferably located upon the wheel 28 of the control column 26 so as to be accessible at all times to the fingers or hands of the pilot for the reception of tactile stimuli or factor measurement indications from the fac tor measuring instruments. By means of the information or indications of-the factors of flight received from the various tactile units, the pilot may control and guide the plane without the necessity in general of referring to .or reading the'various instruments located on the instrument board. v

The preferred arrangement of the various tactile units and the corresponding tactile instruments for measuring various essential factors of tlight is indicated diagrammatically in this view (Fig. 2) which shows thewheel grasped by the hands of the operator in the usual way the various tactile units being positioned with relation to the wheel so as to be under the ,flngers and thumbs of the pilot in the normal position of the hands during flight. In this view. the tactile altimeter instrument I" is indicated as being operatively connected by means of the. connection I02 to the 7 awaocc tactile unit I03, mounted in relation to the wheel so as to be accessible to the right hand thumb of the operator. Similarly the tactile air-speed indicator 2Illl'is indicated as operatively connected by means of the connection 202 to the tactile unit- 203, mounted atthe left side of the wheel 28 so as to be accessible to the left hand thumb of the pilot. In order to indicate through tactile means the deviations of the plane from a given direction during flight and also to indicate the degree of turn by means of such tactile units, a tactile turn indicator 330 is provided, which indicator is suitably mounted and connected in circuit with the tactile units 302, 303, 308 and 338 located under therim of the wheel on the right hand side thereof and with the tactile units 3 I2, 3 I 3, 3H; and 338 similarly located under the said rim at the left hand side thereof. These turn indicator tactile units or buttons are preferably mounted in connection with the wheel so as to be flush with the undersurface of the rim in the inoperative position of the units, the buttons projecting be yond the surface of the rim in the raised or operated positions.

The tactile turn indicator 333 is preferably constructed similar to the ordinary turn indicator and has the contact points 322, 323, 326 and 328 at the right of the middle position of the pointer 333 and has the contact points 3I2, 3I3, 3M and 333 at the left of the middle position of the pointer, the various contact points or contact bars being preferably positioned in an are 323 as in the ordinary turn indicator. The positions of the contact points to the right and left of the center of the dial correspond in general to one, two, three and four width turns, or pointer positions of the turn indicator. 4

The contact points on the right side of the dial are suitably connected for operation of the corresponding tactile units by means of suitable elements and connections 332, 333, 338 and. 333, by which the tactile buttons or units 302, 303, 306 and 308 may be operated. In a. similar manner the contact points at the left side of the dial of the turn indicator are operatively connected by suitable elements 352, 353, 356 and 358 by which the corresponding tactile buttons or units M2, 3 I3, 3I3 and M8 may be operated.

A specific form of construction or embodiment of the invention as applied to a turn indicating. device is illustrated and described in detail in con- It .will be apparent that by the use of the simple 7 tactile units mounted in the manner shown, the pilot may guide the plane substantially by the sense of touch in receiving the measured indications of the instruments by which he is informed of each factor independently, although in a coordinated manner, through the movement or positions of the various tactile units or buttons with which his fingers or hands are in contact or may contact to receive the tactile stimuli or information as to the corresponding factors of flight.

' Referring more in detail to the invention as applied for the determination of elevation by means of the tactile altimeter device or levelometer I03, and transmission to the pilot of measurements thereof by means of tactile stimuli, it will be understood that the operative mechanism of the device is preferably independent of the altimeter of the instrument board as above stated.

In its preferred form, the tactile altimeter device I33 comprises a casing I06 (Fig. 8) which is open to the atmosphere, and within which is mounted the aneroid bellows I08, which is preferably mounted on or connected to the casing I06 by a suitable metallic connection IIO attached to the adjacent side I I2 of the said bellows. Connected to the opposite side I I3 of the bellows is a post member I I8 which is rigidly attached thereto so as to move with the wall II3,of the bellows with changes or fluctuations in pressure on the walls of the unit.

The post member H8 is positioned with relation to abridge member II8 within the casing so as to pass through an opening I28 therein, the said bridge member being preferably in the form of a Y having thearms H9 and I2I,as shown more particularly in Fig.5 of the drawings. This member I I8 serves as a wall or part of an interior or supplementary casing I22, in connection with which the aneroid bellows I38 is mounted, thus forming a rigid construction. The bridge member M3 is preferably held in place by means of two bolts I23 and I26 (see Fig. having the nuts I23 and I33 thereon to secure the arms of the bridge member M3 in place.

The post member H3 is preferably constructed with a shoulder or stop member I32 located thereon so as to be at the left side referring to Fig. 8 of the drawings of the bridge member I I8, and with a stop member, as nuts I33 on the other side of the bridge member on the end of the post member. The positions of these stop members are so adjusted as to give the desired limits of movement of the post member IIB on each side of the opening I23.

Connected to the post member H3 is a bar member I33 (Fig. 5) having a knife edge I33 (Fig. 8) thereon, the bar member being preferably held in place on the post member by means of a slot I33 in the post member as shown more particularly in Fig. 5 in cross section. The knife edge I38 of the bar member I33 is adapted to contact with a spring member I32, preferably of the cantilever form, the spring member being mounted on a bar member I33 as an anchorage. The spring member I32 is preferably constructed with two branch members I36 and I38 between which the post H3 is mounted in position so that the knife edge I38 on the bar I33 traverses the opening I33 and bears on the branch members as shown more particularly in Fig. 5, whereby the spring member is deflected to a greater or less extent by movements of the knife edge bar, causing movement around the bar member I33 as a pivot.

The bar member I33 to which the spring member I32 is ,attached'and by means of which the spring member may be rotated 'or shifted in position to produce a predetermined tension in the spring member, is preferably mounted between blocks or supporting bars I52 and I 53 (Fig. 5), being supported between the said block members by means of suitable bearing members, such as set screws I56 and I58, between the ends of which the bar member I33 is pivotally mounted. The bar member is preferably connected to alever or rod member I33, at the central portion thereof, and is preferably connected to a mechanism by means of which the registering device, or tactile element, may be relation to the predetermined setting orvalue. The mechanism by means of which this is accomplished comprises preferably a movable member I62 carrying external screw threads I54 thereon, said external threads being adapted to engage the corresponding internal threads I66 of. the movable member I55, the latter member having external threads I'III engaging with corresponding internal threads in a bushing member I12, which bushing member is preferably rigidly connected to the casing by means of set screws III and H5. The movable member IE5 is preferably operatively connected to a dial member or knob I'Ill by means of pins I and I 82, these pins being rigidly connected to the knob member H5 and the movable member I havingppenings I85 and I86 in a flange portion I88 of the movable member I55 so that as the knob H8 is turned the movable member I68 may move inwardly or outwardly relative to the knob. The bushing member I72 preferably carries an external groove I95 which is adapted to be engaged by the end of a set screw I92 carried by the knob member I'Iil so that as the knob member is turned it is maintained in a fixed position relative to the casing I56. The number of screw threads on the movable rod I52 and on the movable member I55 are so adjusted in ratio asto-permit a delicate adjustment of the level adjusting mechanism by the turning ofthe dial or knob are. The differential thread combination provides in effect a Vernier or micrometer adjustment whereby the apparatus may be set to measure pressures with reference to a predetermined altitude or pressure, as will be herein- 7 after more fullydescribed.

In order to suitably amplify or magnify the fluctuations or movements of the aneroid bellows which is transmitted to the post member III; .and from thence through the knife edge I35 to the spring member I52, a flexible arm III-II is provided, which arm is preferably supported on and attached to a bar member I55 which is so pivoted with relation to the spring member as to provide a leverage by means of which the movements are suitably multiplied or amplified in ratio to produce the desired sensitivity of the mechanism.

The ends of the bar member I55 preferably contain slots III and I55 by means of which the bar member I55 is mounted on spring members I55 and IN, suitable set screws or supporting means being used which engage the spring members in the said slots, thereby providing means for pivoting it and permitting the bar member I95 to rotate or oscillate slightly above its axis on the points of suspension on the spring members.

The spring members I55 and It'll are preferably mounted on suitable block members I55 and II I, being held in place by set screws I25 and I25 (Fig. 5) at the upper end portions thereof and by means of set screws, as I15 at the lower ends thereof, as shown more particularly in Fig. 4 of the drawings. In order to permit oscillation of the bar member I96 and to hold the bar in place on the spring members I05 and I01, suitable set screws II3 and H5 are provided on the undersides of the bar at the slot portions, and set screws, as I63 (Fig. 4) are provided at the upper portions thereof, by means of which the bar member I96 is rigidly attached to the said spring members I05 and I01. In order to suitably vary the tension in the spring members I05 and I01, set screws I15 and I'Il aoraoea (Figs. 4 and 9) are provided which pass through the outer portions of the block members I59 and III and engage the inner surfaces of the slots IIII and I53 by which the width of the slot in the block members may be varied somewhat, thereby correspondingly varying the tension in the spring members.

Mounted on the bar member I55 are suitable set screw members IZ'I and I29, the ends of which come to a point and engagethe arms or extensions I46 and I58 respectively of the spring member I 32. The said set screws are preferably held in placeabove the axis of the bar member I96 by means of suitable ears or extensions III and I33. It will be noted that the spring member I42 engages the ends I55 of the screws III and I29 above the axis of the bar to which the long flexible arm I5 3 is attached, thus forming a lever of the third class by which movements in the plane at the points of the set screws I21 and I29 will be multiplied at the end of the lever arm I95.

Referring again to Figs. 7 and 8 of the drawings it will be apparent that the arm I 55 is mounted between two contact points I35 and I37 of the circuit closing member IIII. As shown more particularly in Fig. 7, these contact points are preferably provided on adjustable set screws I61 and I59 which are carried on suitable insulating members I 59 and I II which are held in place by means of bolts M3 and I55 which pass .through the arms I I! and M5 respectively, suitable spacing members between the contact points of the circuit closing member being provided, such as insulating blocks Iill, I95, I95 and MI. The arms III and M9 are suitably supported on the block members I55 and III by means of set screws I5I and I53 for example, as indicated in Fig. 5 of the drawings.

On the arm I95 is mounted contact member I95 which is adapted to engage and contact with the points I35 and I37, so as to close a circuit through the leads from the wire 52 to the wire II? or to the wire 55 as movement of the arm I55 takes place in the proper direction for contact.

In order to operate the tactile unit I55, connected to the tactile altimeter device It, a motor 35 is connected in circuit with a relay mechanism 35 which is operated when the arm I54 is moved in one direction or the other through movement of the aneroid bellows I58, by which contact of the member I 55 is made with either the contact point I35 or I3! of the circuit closing member I5I (see Fig. 7). By the operation ,of the motor 58, the tactile button I55 of the tactile unit IIII is moved in proportion to the rotation of the motor in either direction, whereby the total amount of travel of the said button I55 represents in a quantitative way the elevation or altitude at which the plane is flying. In the preferred form of the invention, the movement of the button I55 is related to the flange I59 of the cylinder portion I5'I, so that the position of the button indicates the elevation with reference to a predetermined elevation or reference level.

Referring more particularly to Figs. 3, 9 and 10 of the drawings, the motor-38 is preferably supported within the casing I06 on one side of the motor by means of rod members II and II at the upper portion of the motor casing and by means of rods I3 and I3 at the lower portion of the motor casing. On the other side of thev motor, a frame member is employed to support the motor and the mechanism directly con arms I8! and I43 by means of which the circuit closing member IN is moved out of contacting engagement with the contact member I38 on the of the arms has taken place corresponding to the position at which the arm I941 has come to rest in indicating a particular altitude.

The supporting frame above referred to comprises the upper rod members I and I5 and the lower rod members H and Il' together with the cross bars or arms I3, I3, and 'II', which support the bosses 2I and II (Fig. 9) and the cross bars or arms 2I and M which support the boss 33 (Fig. 8).

The boss member 23 serves as a bearing for one end of the motor shaft 23, the other end of the shaft being supported in a bearing within the portion 35 of the motor housing.

The boss member 33 together with a boss member 5i serve as bearings for the shaft member 83, which carries a thread 53 at the middle portion thereof and a worm 85 at its upper portion.

The shaft 29 of the motor 38 carries a worm 53 which meshes with the worm gear 51 mounted on the shaft 83, by means of which the shaft 83 is rotated when the said motor is operated.

In order to operate the piston I II to which the tactile button or piston I55 of the tactile unit IE3 is connected, the screw thread 53 is designed to engage a corresponding internal thread in a boss M (Fig. 4) of a movable arm member 83 to which piston member i I! is connected through arms I5 and I1 (Fig. The movable member 83 is preferably prevented from rotation in its movement along the shaft .89 by providing an opening in the boss or enlarged portion 81 of the arm member 63, which engages a rod 83, the rod 83 being fixed to the framework of the motor in any suitable manner, being preferably secured in a boss II as shown more particularly in Figs. 8 and 9 of the drawings. The movable member 63 is guided in its movement so as to move in a vertical direction along the shaft'33. The forward end I3 of the member 83 is preferably connected to rod members I5 and H by means of a pivotal connection as shown more particularly in Fig. 8. By the movement of the piston member III in the casing portion I9, the button member I55 of the tactile unit I38 is correspondingly operated as has been'heretofore explained.

In order to operate the arms I81 and I83 which carry the circuit closing member IN, by the movement of which a circuit is completed to operate the motor 38 when a change in pressure on the aneroid bellows I88 occurs, the worm 8i on the shaft 83 engages a worm gear 83 which is mounted on a rotatable sleeve member 85 carried between the supporting members B'I and 83. In order to prevent longitudinal movement of the sleeve member 85 in the supports, the sleeve member is preferably provided with two grooves, one on each side of the sleeve, the groove in the portion of the sleeve carried by the support 8? being engaged by a set screw 3| and the portion carried by the support 83 being engaged by a set screw 33.

The sleeve member 85 is preferably internally threaded and carries a threaded rod 35 which is adapted to be moved in a forward or return direction depending'upon the direction of rotation of the motor 38. The rod 35 is preferably connected thereto by means of the ears of a yoke member 99 as shown in Figs. 8 and 10, the rod 31 being in turn similarly attached to a connection I67, attached to the arms III? and I43, by

- means of which the arms are actuated.

The motor 38 is preferably connected in circuit so that it may operate in a forward or reverse direction, depending upon whether the primary circuit, including the battery 48, is completed by the closing of the switch including the contact points I38 and I31, or by the closing of the switch including the contact points I98 and I35 (see Fig. 13).

I pivoted on a suitable pivot or bearing 58, so as to pivot thereon, and is normally held in neutral position by means of coil springs 58 and 88, mounted so as to bring the armature away from the contact points when the current through the coils of the magnets is broken. On the upper part of the armature 53 is preferably mounted an insulating rod 82 having conductors 88 and 88 positioned thereon so as to contact with contact members 88 and III or I2 and I8 respectively so as to close the circuit-in one or the other direction through the armature and field winding of the motor 38. In the preferred "construction the conductor or contact bar 88 is mounted between the contact members 88 and I2 so as to close a circuit, the particular circuit closed depending upon whether the armature 58 of the relay 38 is moved in a clockwise or counterclockwise direction on the pivot 58. The bar or contact member 86 is similarly mounted on the rod 82 between the conducting members or contact members I0 and I3, so as to close the circuit in one or the other direction simultaneously with the closing of the other circuit when the contact member or bar 64 moves into contact with either of the contact members between which it is mounted.

In the construction shown, the field winding 78 of the motor 38 is connected to the battery I8 by a lead wire 88, being connected to the negative pole of the battery as shown. The lead wire I 82 serves to connect the positive pole of the battery with the contact member 88.

The contact member 88 is connected by a lead wire 88 to a brush 88 of the motor, the lead wire 88 being connected to the other brush 38 of the motor and to the contact'member III. The contact member 88 isalso connected by a lead wire '32 to the contact member I8. Similarly the contact member I8 is connected by a lead wire 38 to the contact member I2. The circuitisccmpleted through the field winding I8 of the motor by the lead wire 38 which connects the other terminal of the field winding with the contact member '88 mounted on the insulating rod 82 as previously described.

connected to a rod member 3I, being piv-otally The battery 88 is connected to the contact point I98 of the movable arm or member I38 by means of a lead wire 82, being connected with the positive pole of the battery 83 as shown. The negative pole of the battery is connected by a lead wire 38 to a relay coil 33 which is mounted on- 1:1; I aoraoea and passes around the armature 54. The coil 39 is connected to the coil 52 by means of a lead wire M and is also connected to the coil 59 by tact point means .of a lead wire 43. The relay coil 52 is directly connected to the terminal contact member 135 by means of a lead wire M and, correspondingly, the relay coil 56) is connected to the terminal or contact member l3? by means of a lead wire 45.

The operation of the relay mechanism is as follows:

When the arm I99 is moved so that the contact point 998 engages the contact point I31, thus closing the circuit from the lead wire 42 to the lead wire 95, a current from the battery 44 passes through the lead wire 32 to the conl98 and from thence to contact point I91 and through lead wire 95 to the coil 50 and through lead wire 43 to the coil 39 and from thence by the lead wire 98 to the negative pole of the battery M. The current in passing through the coil 59 energizes the magnet 46, and similarly the current through the coil 39 energizes the armature 59 whereby the armature moves in a counterclockwise direction around the pivot 56 so as to cause contact between the armature Wand the end of the core or field piece at. In this position of the armature 59, the member 9d engages the member 68 and the member 66 engages the member 119, thus closing the circuit between these members so that current flows from the battery l8 through the lead 82 to the contact member M and from thence to the contact member 58 and through the lead wire EM to the brush member 86 and through the armature M of the motor 98 to the brush member 99 and from thence through the lead wire 83 to the contact member it, then to the contact member 66 and from thence through the lead wire 99 to the field coil 79 of the motor and then through the lead wire 39 back to the negative terminal of the battery'ifi; The current from the battery it thus causes the motor 39 to rotate in one direction, as a clockwise direction for example, whereby the arms il l'l and M9, are actuated through the gear train, as has been explained in connection withFig. 3 of the drawings, in a direction tending to bring the arm H94 away from the contact member closing the primary circuit through the battery 39. With the contacts as assumed, the arms hill and M9 are moved in a direction to open the circuit at the contact points HM and Mill and as soon as the circuit is broken through the contact points,

the current through the coils 99 and 39 is interrupted, whereby the corresponding magnets are de-energized and the spring member 58 then returns the armature 54 to its central or neutral position, in which it is then held, through the equal tension of the springs 58 and 69. The movement of the armature 54 away from the magnet 39 breaks the contact also between the members 66 and 19, which interrupts the current flowing from the battery to the motor 38, whereby the motor is stopped.

- When the arm I94 is moved so that the contact point 198 engages the contact point 035, current from'the battery passes through the lead wire 42 to the contact point I98 and from and the armature 59, causing the armature to move to the right into contact with the field piece 98. As the armature moves to the right, or in a clockwise direction, the member 64 contacts with the member l2 and the member 56 contacts with the member M closing the circuit in which these contact members are located, whereby current from the battery 78 passes through the lead wire 82 to the contact member '64 and from thence to the contact member 172, then through the lead wire 94 to the lead wire 88, then to the brush 90 and through the armature M of the motor to the brush 86, and from thence through the lead wire 84 to the lead wire 92, then to the contact member l4 and from thence to the contact member 66, then by the lead wire 96 to the field winding l6 and from thence through the lead wire 89 to the negative terminal of the battery 18.

This causes the motor 38 to rotate in the opposite or counterclockwise direction, causing the arms Ml and M9 to be actuated, by means of the levers and intermediate gearing, in a direction so as to move the contact member l35 away from the contact member I98, thus opening the circuit through the battery M and interrupting the current to the relay coils 52 and 39, whereby the corresponding magnets are de-energized. As the magnets H8 and 54 are demagnetized, the spring 69' moves the armature 59 into its central position, by which the contact members 66 and I2 and also the members 66 and "M are separated, thus interrupting the current irom the battery it to the motor 39.

As soon as the motor 38 stops it remains stationary or dead until movement of the bellows 098 in either direction causes the arm 899 to move so as to close the circuit between the contact points E98 and i9 1, or the contact points E98 and M5, whereby the motor is again placed in circuit with the battery it repeating the operation as above described.

As the motor 39 operates in one direction or the other, the movable part Ml which is directly connected to the tactile button or piston.l55 will be correspondingly operated, the said button being actuated by means of a Bowden wire or other suitable connection M12 as indicated more particularly in Figs. 2 and 3 of the drawings.

It will be understood that the arm M9 is sufliciently flexible so that as movement of the arms Mill and M9 causes contact between the adjacent contact points with greater or less pressure, the arm 194 may be bent to a greater or less extent without interfering with the operation of the mechanism.

It will be understood also that as the premure on the aneroid bellows 998 increases, the post member M6. will move to the left, referring to Fig. 8, thus moving the knife edge I38 to the left, that is, in the same direction, and flexing the spring member I42 toward the left, by which the pressure on the points I85 of the screw members 921 and H29 ,is decreased, whereby the arm I94 moves to the left, or in a counterclockwise direction. It will be apparent, on the other hand, that as the pressure on the aneroid bellows I08 decreases, the movement of the parts takes place in the opposite direction, that is, to the right, whereby the arm member I 94 is rotated in a clockwise direction;

Referring again to Fig. 8 of the drawings, as the arm I94 moves toward the right, or in a clockwise direction corresponding to a decrease in pressure on the aneroid bellows, the contact aovaoaa point It of the arm I94 moves into contact with the contact member I39, whereby a circuit from the lead wire 02 to the lead wire is closed, -by which the relay mechanism 90 is operated, causing the switch mechanism 01 to close, whereby the motor 90 is operated in a clockwise direction, for example. r o

It will be obvious that by making contact be-. tween the contact point: I98 on the arm I90 and the point I37 of the circuit closing member I ti, which takes place through the movement of the arm wt to the left, referring to Fig. 13, which corresponds to an increase in pressure on the aneroldbellows I08, the circuit from the lead wire It to the lead wire 09 is closed, whereby the motor will actuated in a counterclockwise direction, for I ple.

The circuit which is closed by the movement of the arm I90 into contact with the contact points I09 or IN is preferably a 2-volt circuit, whereas the circuit which is closed through the operation of the switch mechanism II to operate the motor 90 is preferably a l2-volt circuit.

I It will be understood from the above description, that the motor 39 serves the dual function of controlling. (l) the movement of the piston I II, by which the tactile element I00 is operated,

' and (2) of controlling the movement of the arms III and M9 on which the circuit closing member II. is mounted, thereby breaking contact between the circuit making contact points I90 and I31! on the one hand, and "I98 and I35 on the other hand, when either of the sets of contact points are in engagement. When the motor is actuated to operate the arms connected to the member It I,

by which contact of the points is broken, the current to the motor is interrupted through the breakirig of the circuit and the motor is stopped.

It will be clear, therefore, that when the plane is flying at the desired level or altitude in accordance with the set of the dial member I18 of the level regulator 95, the contact point I98 is in its mid position between the contact points I35 and I 31, and the tactile element I55 will be flush with the upper flange I59 of the tactile unit I04. When the plane is flying at a different level from the predetermined level, on the other hand, the arm member I94 will be .swung in a direction to 'make contact between the contact member I98 through the tactile unit the information or indication as to the altitude of the plane, whereby the altitude of the aircraft may be corrected to cor- 'respond with the predetermined altitude for which-the regulator 35 is set.

It will be apparent also from the drawings and I the above description that the position of the set screws I21 and I29 may be regulated for contact with the arms I49 and I48 of the springmember I42, so that at a pressure corresponding to the pressure at an altitude of 20,000 feet above sea level, for example, the arms I48 and I48 just touch or contact with the ends of the set screw members I21 and I29 when the arm I94 is in its v mid-position.

)which definitely limits the arc of travel of the The knob member I18 is, as above described,

ously be determined by the conditions underwhich the plane is to be operated, although for ordinary commercial flying the maximum range is preferably adjusted for about 18,000 to 20,000

feet altitude. The screw threads of the adjusting device are preferably designed'so that as the screw member I08 is screwed in clockwise'direc tion, into the bushing I12, it travels to the right at a rate of 24 threads per inch with respect to the bushing member I'IZ, but at the same time it screws also to the right on the screw member I02 at the rate of 32 threads per inch, so that the resultant movement of the screw member I62 is a movement to the right-corresponding to 8 threads which is the equivalent of amction imparted to a screw member having 96 threads to the inch.

This differential thread combination corresponds to a vernier adjustment and gives a very sensitive or micrometer adjustment to the operative screw member ItI by means of which a predetermined tension. is imparted to the spring member I92 corresponding to the desired altitude. It will be apparent that when the screw member I92 is moved to the right, referring to Fig.8 of the drawings, the arm I00 is rotated correspondingly around the bar member I M on the pivots I50 and I50 (Fig. 10) by which a corresponding clockwise direction is imparted to the bar member III which releases tension to a corresponding extent on the spring member I92. It will be clear that when the knob member I'It is turned in the opposite direction, the bar member is rotated slightly in a counterclockwise direction whereby the tension in the spring member I02 is proportionately increased.

It will be understood that by means of this adjustment; it is'possible to reduce the tension in the spring member IIZ by a predetermined arms I46 and I48 of the springmember I42, It

will be clear, therefore, that as the dial I18 is moved so as to reduce the tension on the spring .member I42, the bar member I44 will be rotated in a clockwise direction, whereby the tension in the spring I42 will bereduced; as a result of this reduction in tension theset screws I21 and I29 on the bar member I98 will bemoved to the left, or in a counterclockwise direction, about the axis of the bar I 98 on the spring members I and I01,

'by whichthe arm I 94 will be moved in a counterclockwise direction, whereby the circuit will be closed through the contacts I98 and I31 to operate the motor 38 and whereby the piston H1 and the corresponding tactile unit I04 will be operated so that the button I55 of the tactile unit will be amount, or in other words to unload the pressure moved into a position belovcthe flange member I59 to indicate the relative distance or altitude below the 'pre-determined desired altitude for which the dial I 18 is set.

It will be obvious that as the plane gradually rises to the predetermined altitude, the element I55 of the tactile unit rises correspondingly, so

that when the predetermined level is reached for flush with the flange the indicating that the plane is flying at the predetermined altitude. If the plane rises above or below the predetermined level during flight the element ltd will be raised or lowered accordingly so that the pilot is continuously informed of the altitude of the plane through the tactile unit without the necessity of reading the altimeter on the instrument board.

It will be understood that while the form of tactile altimeter device, as described, represents the preferred form of the invention, various changes or modifications may be made without departing from the principle of the invention, as will be apparent to those skilled in the art. While the use of a separate tactile altimeter instrument connected to the corresponding tactile unit as above described is preferred, it will be understood that in connection with the two altimeters which are usually employed on the instrument board, one of the altimeters might be attached to and operated in connection with the tactile unit I04 as described more particularly in connection with Figs. 4 to 13 inclusive of the drawings, without danger due to instrument failure. By the use of two such altimeter instruments, one for visual reading and the other for combined visual and tactile indications, the factor of safety in connection with these instruments is at least-equal to that obtained by the use of two visual instruments in the manner now generally used.

Referring now to the tactile air-speed mechanism as indicated in Fig. 2 of the drawings, and more particularly shown in Fig. 14, the device 200 illustrated is an air-speed device for determining the speed of aircraft, the speed indications bein transmitted to the operator through tactile stimuli by means of the tactile. unit 204 operated by means of a Bowden wire or the like member 202 in substantially the same manner as described in connection with the altimeter unit.

The dynamic pressure tube 206 and the static pressure tube 201, through which air pressure is transmitted to the aneroid bellows 208 of the speed indicator, are preferably mounted on the wings of the plane in the usual manner, the dynamic pressure tube 206 communicating with the interior of the aneroid bellows 208 and the static tube 201 communicating with the chamber 2l0 on the outside of the bellows.

The operating elements of the air-speed device are mounted within a suitable casing 212 in substantially the same manner as has'been described in connection with the tactile altimeter mechanism, except as to further details of construction to which reference will be specifically made. The pressure developed on the wall- 209 of; the aneroid bellows 208 is a differential pressure and represents the difference in pressure developed by the kinetic energy of the air exerted on the column of air in the dynamic tube 206 and the static air pressure transferred to the chamber 2l0 through the static tube 201.

It will be understood that the differential pressure on the wall 209 of the bellows unit is created through the speed or movement of the plane in such a manner that as the air-speed increases, the pressure on the wall of the bellows unit increasesproportionatelyand moves to the right with reference to Fig. 14 of the drawings, against the resistance of a spring unit, as 282, which may be mounted so as to directly contact with the arm 294 of the amplifying means. A similar spring member 281 is preferably mounted between the wall 209 of the bellows unit and a projection 295 On the aovacea arm 290 by means of which movements of the wall 200 are transmitted to the arm 2% in a manner somewhat similar to that in which movements of the aneroid bellows I00 is transmitted to the arm N4 in the tactile altimeter device.

In the tactile air-speed measuring device the pivoted arm 294 is preferably similar to the arm I of the altimeter device, which arm serves to magnify or amplify the movements of the wall 209 of the aneroid bellows 208, the arm being mounted between the contact points 235 and 231 of a circuit closing member 26! attached to arms such as 240, as has been fully explained in connection with the tactile altimeter device. It will be understood that the relay device 236 and the motor 238 are in circuit in the same manner as has been described more particularly in connection with Fig. 13 of the drawings.

In the embodiment of the invention as illustrated in Fig. 14 of the drawings, it will be noted thatthe tactile unit 204 is shown directly connected to the rods 215 which is operated in turn by means of the movable member 263 carried on the threaded portion 259 of the shaft 262 similar to the shaft 49 shown in Fig. 8 of the drawings. The tactile unit 204 is preferably mounted so as to move in a forward and return direction in a cylindrical portion 216 of the casing 212, the flange member 200 serving as a reference level in determining the speed indication through the sense of touch. The portion 216 of the casing has preferably an enlarged part 219 which may be provided with packing 210 to permit longitudinal movement of the tactile element and to hold the element laterally in position.

It will be understood from the above description that as the speed of the plane decreases the spring member 282 will force the arm 294 to the left against the spring member 28I which moves to the'left on the wall 209 of the bellows due to the decrease in pressure thereon. It will be understood that as the arm 294 moves to the left a circuit is completed through the contact members 298 and 231 causing operation of the relay mechanism 236 and of the motor 230 in the manner explained in connection with Fig. 13 of the drawings. By the operation of the motor 238, the movable member 263 and the rods 215 will be operated causing corresponding movement of the tactile element 204.

The tactile air-speed mechanism is preferably mounted in a position in the plane so that the rod 'inember 215 may move in substantially a vertical direction so as to directly operate the button or unit 204 on the wheel or stick in a position accessible to the hands of the pilot. It will be understood, however, that instead of the direct connection, as illustrated in Fig. 14 of the drawings, a Bowden wire connection 202 or suitable hydraulic connection may be employed for transmitting movements from the piston or rod members 215 to the tactile .unit 204.

In connection with the tactile element 204, I may employ a suitable form of device by means of which the position of the tactile element 204 may be determined through the sense of touch 7 so as to obtain the actual speed indication. I may, for example, provide a-groove member in the top portion of the casing 216, the groove being provided with reference notches so that the pilot may, through the sense of touch, determine the position of the unit 204 with reference to the notches. For this purpose a series of aoraosa tive to a predetermined or desired speed may also be determined by substantially the same manner as provided in connection with the tactile altimeter unit. For this purpose I may provide a dial or speed regulating unit 53, the position of which is indicated in Fig. 1 of the drawings, by means of which readings of the tactile unit 3M will be referred too the flange 230 to indi- I) cate whether or not the actual speed is greater or less than the predetermined desired speed of the plane for which the regulator 55 has been set. The manner in which this may be accomplished and the mechanism required will be clear to those skilled in theart by reference to Figs. 4 to 10 of the drawings together with the corresponding description and need not therefore be repeated in detail.

It will be apparent that many modifications in the form of speed device'may be made. I may, for example, employ a simplified construction in which a piston is subjected to the dynamic pressure of the air during flight, the device being open to the atmosphere on the opposite side of the piston and subjected to spring pressure so that the movement of the piston is substantially proportional to the differential pressure between the dynamic and static air pressure. The piston may be connected to a coil spring for example, as a weighing device, the piston being operatively connected to a tactile unitby means of which the relative speed of the plane may be determined through the sense of touch. Another simplified construction suitable for relative speed measurements comprises an indicator of the anemometer type in which four cups, subjected to the dynamic pressure of the air, revolve horizontally, turning a vertical shaft and operating a governor at the top end. In this instrument, the lower piston of the tactile unit is connected to the top side of the governor and as variations in speed'occur the expansion or contraction of the governor actuates the tactile unit by which the relative speed of the plane may be determined through the sense of touch.

It will also be understood that in place of th form of tactile speed indicator, as above described, I may, if desired, employ the form of mechanism shown and described inconnectionwiththealtimeter unit I00, which mechanism may be connected to the aneroid bellows 206 of the speed indicating device by using a spring as I42 and connected parts in exactly the same way as the associated mechanism of the altimeter device is connected to the aneroid bellows thereof.

While the various forms'of tactile stimuli transmitting devices, as described, contemplate the use of a Bowden wire as a means of transmitting movement from a primary mechanism for measuring a particular factor in flight to a tactile unit by which the measurement is indicated, it will be understood that the transmission to the tactile unit may be made by other suitable means.

A hydraulic system may be employed, for ex-- ample, for transmitting movement from the original measuring device to the tactile units or buttons. The tactile units maybe operated, for example, through the medium of castor oil maintained in a metal hose or tube connected to the part of the mechanism in which the movement of the aneroid bellows has been suitably amplified.

It will be obvious that castor oil, for example, has

the advantage of a low freezing point and high boiling point and that the viscosity of this oil remains substantially constant through such a range of temperature as would ordinarily be encountered in connection with commercial flying. This oil has furthermore a low coefficient of expansion; and in transmitting movement to the tactile unit, the amount of deviation or change due to expansion or contraction within the ordinary range of temperatures would beentirelyneg-. It will be understood, however, that some.

ically in Figs. 2 and 17 of the drawings, by which,

the measurement or indication of the degree of turn during flight is transmitted to the pilot by means of movement of the movable elements of the tactile units, or by other tactile stimuli; by this means also the pilot is informed of deviations of the plane or aircraft from the set course.

The numeral 333 designates a turn indicator of the usual form having a pointer m which travels over an arc 32d having a series of contact points 322, 323, 326 and 323 to the right of the middle position of the pointer and contact points 332, 333, 336 and 338 to the left of the neutral or middle position of the pointer. These contact points are each connected with corresponding "buttons or tactile elements 302, 3%, 306, 338 and M2, 3%, 3l6, am which are preferably located in such a position on the control column or stick as to be within reach of the fingers of the pilot, as for example on the under surface of the wheel 26.

The contact points 322, 324, 326 and 328 at the right on the turn indicator are connected through lead wires 332, 3 44, 346 and348, to the corresponding tactile units 302, 304, 306 and 308. In a similar way the contact points 332, 334, 336 and 336 to the left of the pointer in the turn indicator are connected by means of wires 332, 334, 336 and 338 to corresponding tactile units M2, M4, 3 i6 and actuated, thus indicating to the pilot the degree of turn or the extentof deviation which is being made from the course.

Referring more particularly to Fig. 17' of the drawings, the battery 360 is shown as connected in circuit with the pointer 316 of the turn indicator 300 by means of a lead wire 310, the op posite pole of the battery being connected in circuit through the lead wire 38!] with the two series of solenoids above referred to, ,the lead wire 380 being connected through the leadwires 362, 364, 366 and 388 to the solenoids on the right of .the wheel 28 and by lead wires 392, 334, 396 and 366 to the solenoids on the left of the wheel 26. It

will be'un'derstood that the circuit from the battery through the solenoids 362, 36 i, 353 and 363 on the right of the wheel 28 is completed by means of the lead wires 3&2, 34 i, 345 and 3458 when the pointer 3i contacts with one of the corresponding contact points on the right of the turn indicator and correspondingly the circuit through solenoids 312, ill l, 316 and 313 is completed through the lead wires 352, 354, 356 and 358 when the pointer engages one of the corresponding contact points on the left of the turn indicator.

It will be understood that the contact bars or contact points of the turn indicator are preferably positioned in such a manner that deviations of the plane up to two degrees from the intended course will not produce actuation of the tactile unitsof the turn indicator device, whereby when the course is maintained within an accuracy of a two degree deviation, the pilot receives no warning signal or movement of the tactile units of the turn indicator.

The following table indicates the preferred arrangement in connection with the contact bars of the turn indicator and the preferred mode of operation of the tactile units in indicating the degree of turn or deviation:

Degree of turn Indication on tactile units Less than two degrees.

Two degrees.

One width turn to right or left, in which contact bars 322 and 324, or 332 and 334 are in circuit.

Two width turn, inwhich pointer 310 is in contact with bars 324 and 326, or with 33.4 and 336.

Three width turn, in which the pointer 310 engages bars 326 and 328 or 336 and 338.

More than a three width turn.

No units raised.

(ontact bar 322 or 332 is n circuit and one button 13 raised.

The first and second buttons. 302 and 304, or 312 and 314 are in raised position.

Second and third buttons are raised; that is, buttons 304 and 306 or 314 and 316 are in raised position.

The third and fourth buttons are raised. that is buttons 306 and 308 or 316 and 318 are in raised position.

Only the fourth button is raised, that is button 308 or 318 is in raised posi tion.

It will be understood that in the above table the terms one width turn, two width turn, etc., refer to the degree of turn of the plane, corresponding to one, two, etc., widths of the pointer 3"] in the turn indicator. A one width turn, for example, means a turn in which the pointer is displaced one width from the middle position and corresponds, in general, to the making of a turn of 180 in about one minute. It will be understood, however, that the degree of turn may vary to some extent depending upon the type of turn indicator used and also upon its adjustment.

It will be noted particularly in connection with Fig. 17 of the drawings that the width of the contact bars may vary somewhat and that the spacing-of the bars may also be varied somewhat by the insertion of varying widths of insulating material between the bars. It will be apparent, however, that it, is desirable to have the. end con- I tact bars, or the bars at the extreme ends of the scale, of greater width than the other bars, so that when the plane is making a maximum degree turn, the fourth buttons, that is buttons 308 or 318, will remain in the raised position so as to give the desired warning to the pilot in' the making of the turn.

As indicated in Fig. 2 of the drawings, the pre- I ferred position of the tactile units of the turn indicator is on the underside of the wheel 28 in such a position that the fingers of the'pilot would naturally fall on the buttons when the thumbs are in contact with the tactile unit 204 of the airaovassa speed device 200 and the tactile unit Hi l of the levelometer or altimeter Hill in the relative posi tions as indicated.

Referring more in detail to Fig. 18 of the drawings, it will be seen that the buttons" or tactile elements, as 302, which are mounted on the under surface of the wheel 28 are substantially flush with the curved surface of the wheel in the re tracted position of the solenoids.

The construction of the solenoids and the manner in which the solenoids may be mounted within the wheel will be apparent from a consideration of Figs. 1, 2, 17 and 18. The wheel 28 preferably contains an interior chamber M3 which communicates with the under surface of the wheel by means of openings 415 in which the buttons, as 302, are mounted. The solenoids comprise the usual coil 471 which is mounted within the tubular core 419 of the electro-magnet. A plunger 448 of the electro-magnet is mounted within a non-magnetic sleeve 450, which in turn is mounted within the tubular core 419 which is of magnetic material. Attached to the plunger 448 is the armature 454 which when a current is passed through the coil is drawn or sucked up by the magnetic field into contact with the ends of the sleeve 450 which acts as a stop, whereby the button 302, mounted on the end of the plunger 448, is brought into its raised position. In order to raise or return the plunger 448 to its initial position after the current through the coil of the solenoid is interrupted, I preferably employ two spring members 456 and 458 which are of the leaf type and mounted on one end of the core 479, as shown more particularly in Fig. 18 of the drawings.

It will beunderstood that the various electromagnets within the wheel are similar and the construction may be varied somewhat if desired, as may be found necessary in connection with specific installations in which the said invention is to be employed.

Referring more particularly to Figs. 15, 16 and 19 of the drawings, it will be apparent that in connectionwith the tactile turn indicator device as applied to the stick or control column 568, the solenoids 510, 512, etc., are in circuit in the same manner as indicated in Fig. 1'7, except that the solenoids are mounted within the stick 568 instead of in the wheel 28.

It will be apparent also that the solenoid members are preferably mounted on the forward side of the stick in parallel relation, so that the hand .ings it will be apparent that the solenoid 510 is shown in the raised position so that the button 514 projects outwardly from the surface 569 of the stick, whereas the solenoid 512 is shown in the retracted position in which the button 516 is flush with the exterior surface 569 of the stick. These solenoids are preferably constructed in the same manner as described more particularly in connection with Fig. 18 of the drawings.

It is to be understood in connection with the turn indicator as above described that I preferably employ a standard commercial form of indicator the details of which need not be herein described. It is apparent, however, that by modifying this commercial form in the manner indicated in Figs. 2 and 17 of the drawings, the tactile 

